# Ratio estimation in StRS
# worker hours lost in company A and B 
xA=c(12,24,15,30,32,26,10,15,0,14) 
yA=c(13,25,15,32,36,24,12,16,2,12) 
xB=c(10,8,0,14,12,6,4,0,8,16) 
yB=c(8,0,4,6,10,0,2,4,4,8)

n.A=10
n.B=10 
N.A=1000 
N.B=1500 
N=N.A+N.B
tauxA=16300 
tauxB=12800
muxA=tauxA/N.A
muxB=tauxB/N.B 

rA=sum(yA)/sum(xA)
rB=sum(yB)/sum(xB) 
s2rA=(sum((yA-rA*xA)^2))/(n.A-1) 
s2rB=(sum((yB-rB*xB)^2))/(n.B-1)
muyRS=(N.A/N)*rA*muxA+(N.B/N)*rB*muxB 
vhatmuyRS=((N.A/N)^2)*(1-(n.A/N))*(s2rA/n.A)+((N.B/N)^2)*(1-(n.B/N))*(s2rB/n) boundmuyRS=2*sqrt(vhatmuyRS)

rbind(n.A,n.B,N.A,N.B,N,tauxA,tauxB,muxA,muxB,rA,rB,s2rA,s2rB,muyRS,vhatmuyRS,boundmuyRS)